Radios including AM and frequency modulation (FM) receivers are well known are pervasive. While such radios have conventionally been manufactured from discrete analog components, trends in the semiconductor industry are leading to the development of digitally-based radio receivers including AM/FM receivers which may be formed in various semiconductor processes including, for example, complementary metal oxide semiconductor (CMOS) processes. In this way, radios can be designed that consume very little space. Accordingly, such radios can be incorporated in smaller and smaller devices.
Thus while standalone radios, which may be present in stereo systems such as home theater systems, table radios and so forth, continue to be manufactured, additional markets are becoming available to incorporate AM/FM radios within portable devices such as portable media players, portable digital systems (PDAs), cellular handsets and so forth.
To operate, an AM radio must have an AM antenna connected to it in order to receive incoming AM signals. However, due to the size of conventional AM antennas, certain problems exist in integrating an AM receiver into a portable device. First, the size of a typical AM antenna such as a ferrite rod antenna can preclude a given antenna's use in many portable products. Second, for the antenna that is included, interference issues may exist. For example, in a portable device that includes a display such as a liquid crystal display (LCD), noise caused by high-speed digital switching in the LCD may cause too much interference for accurate recovery of incoming AM signals by the AM antenna. Typically, an AM antenna should be separated from such a display by more than at least 6 inches. This may be difficult or impossible in a portable device. Thus there are various issues with regard to incorporating an AM receiver in a portable device.